• Asian-Australasian Journal of Animal Sciences
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• 제22권10호
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• pp.1391-1399
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• 2009

Two hundred and sixteen 68-week-old Hy-Line brown laying hens were used in a 6-week feeding trial to compare the efficacy of phytases Optiphos (OPT) and Natuphos (NAT), which were isolated from Escherichia coli and Aspergillus niger, respectively. Hens were randomly allotted into six treatments with six replications (six layers in three adjacent cages) per treatment according to their initial BW. The hens were then subjected to one of the following dietary treatments: i) Positive Control (PC; available phosphorus (AP) 0.4%); ii) Negative control (NC; AP 0.2%); iii) NAT1 (NC+250 FTU/kg NAT); iv) NAT2 (NC+500 FTU/kg NAT); v) OPT1 (NC+250 FTU/kg OPT); vi) OPT2 (NC+500 FTU/kg OPT). Feed intake, egg production, egg quality, apparent nutrient digestibility and serum P and Ca concentration were evaluated to compare the effect of the two phytases. Feed intake and eggshell thickness were not affected by the treatments. Superior effects (p<0.05) of OPT were only observed in egg production and egg weight compared with NAT. Characteristics such as eggshell breaking strength, apparent digestibility of N, Ca and P and serum P concentration were equally increased with the supplementation of both phytases (p<0.05), where no significant difference was observed in those characteristics between PC and phytase supplementation at 500 FTU/kg. Equally effective improvements (p<0.05) were also observed in egg production and DM digestibility, where no improvements were observed (p<0.05) between the PC group and the groups with phytase supplementation at 500 FTU/kg. Equal increases in the serum Ca level were observed when the groups with phytase supplementation were compared to the PC group. Overall, the results of this study suggest that NAT and OPT are equally effective at liberating phytate-bound complexes when included in 0.2% available phosphorus diets for 68-week laying hens; either source of phytase can be fed to commercial 68-week laying hens at 500 FTU/kg to correct the negative effects associated with a 0.2% available phosphorus diet. In conclusion, either source of phytase can be fed to commercial first cycle laying hens at 500 FTU/kg to effectively replace inorganic phosphorus when economically justified.

• Journal of Microbiology and Biotechnology
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• 제24권10호
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• pp.1413-1420
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• 2014

Phytate is an antinutritional factor that impacts the bioavailability of essential minerals such as $Ca^{2+}$, $Mg^{2+}$, $Mn^{2+}$, $Zn^{2+}$, and $Fe^{2+}$ by forming insoluble mineral-phytate salts. These insoluble mineral-phytate salts are hydrolyzed rarely by monogastric animals, because they lack the hydrolyzing phytases and thus excrete the majority of them. The ${\beta}$-propeller phytases (BPPs) hydrolyze these insoluble mineral-phytate salts efficiently. In this study, we cloned a novel BPP gene from a marine Pseudomonas sp. This Pseudomonas BPP gene (PsBPP) had low sequence identity with other known phytases and contained an extra internal repeat domain (residues 24-279) and a typical BPP domain (residues 280-634) at the C-terminus. Structure-based sequence alignment suggested that the N-terminal repeat domain did not possess the active-site residues, whereas the C-terminal BPP domain contained multiple calcium-binding sites, which provide a favorable electrostatic environment for substrate binding and catalytic activity. Thus, we overexpressed the BPP domain from Pseudomonas sp. to potentially hydrolyze insoluble mineral-phytate salts. Purified recombinant PsBPP required $Ca^{2+}$ or $Fe^{2+}$ for phytase activity, indicating that PsBPP hydrolyzes insoluble $Fe^{2+}$-phytate or $Ca^{2+}$-phytate salts. The optimal temperature and pH for the hydrolysis of $Ca^{2+}$-phytate by PsBPP were $50^{\circ}C$ and 6.0, respectively. Biochemical and kinetic studies clearly showed that PsBPP efficiently hydrolyzed $Ca^{2+}$-phytate salts and yielded myo-inositol 2,4,6-trisphosphate and three phosphate groups as final products. Finally, we showed that PsBPP was highly effective for hydrolyzing rice bran with high phytate content. Taken together, our results suggest that PsBPP has great potential in the animal feed industry for reducing phytates.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.220-221
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• 2001

Phytic acid (myo-inositol 1,2,3,4,5,6-hexakisdihydrogen phosphate) is one of the major storage form of phosphorous in the seeds of plants, which are the principal components of feed stuffs. Monogastric animals like Pigs and poultry as well as fish lack phytase activities in their digestive system and most undigested phytic acid was excreted in their manure. (omitted)

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.177-187
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• 2014

Microbial phytases are enzymes with biotechnological interest for the feed industry. In this article, the effect of spray-drying conditions on the stability and activity of extracellular phytase produced by R. microsporus var. microsporus biofilm is described. The phytase was spray-dried in the presence of starch, corn meal (> $150{\mu}m$), soy bean meal (SB), corn meal (< $150{\mu}m$) (CM), and maltodextrin as drying adjuvants. The residual enzyme activity after drying ranged from 10.7% to 60.4%, with SB and CM standing out as stabilizing agents. Water concentration and residual enzyme activity were determined in obtained powders as a function of the drying condition. When exposed to different pH values, the SB and CM products were stable, with residual activity above 50% in the pH range from 4.5 to 8.5 for 60 min. The use of CM as drying adjuvant promoted the best retention of enzymatic activity compared with SB. Spray drying of the R. microsporus var. microsporus phytase using different drying adjuvants showed interesting results, being quite feasible with regards their biotechnological applications, especially for poultry diets.

• Journal of Microbiology and Biotechnology
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• 제26권10호
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• pp.1717-1722
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• 2016

A novel phytase of Acidobacteria was identified from a soil metagenome, cloned, overexpressed, and purified. It has low sequence similarity (<44%) to all the known phytases. At the optimum pH (2.5), the phytase shows an activity level of 1,792 μmol/min/mg at physiological temperature (37℃) and could retain 92% residual activity after 30 min, indicating the phytase is acidophilic and acidostable. However the phytase shows poor stability at high temperatures. To improve its thermal resistance, the enzyme was redesigned using Disulfide by Design 2.0, introducing four additional disulfide bridges. The half-life time of the engineered phytase at 60℃ and 80℃, respectively, is 3.0× and 2.8× longer than the wild-type, and its activity and acidostability are not significantly affected.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.930-935
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• 2015

A phytase gene was identified in a publicly available metagenome derived from subsurface groundwater, which was deduced to encode for a protein of the histidine acid phosphatase (HAP) family. The nucleotide sequence of the phytase gene was chemically synthesized and cloned, in order to further overexpress the phytase in Escherichia coli. Purified protein of the recombinant phytase demonstrated an activity for phytic acid of 298 ± 17 µmol P/min/mg, at the pH optimum of 2.0 with the temperature of 37℃. Interestingly, the pH optimum of this phytase is much lower in comparison with most HAP phytases known to date. It suggests that the phytase could possess improved adaptability to the low pH condition caused by the gastric acid in livestock and poultry stomachs.

• Asian-Australasian Journal of Animal Sciences
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• 제14권4호
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• pp.567-586
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• 2001

Gastrointestinal tract of ruminants as well as monogastric animals are colonised by a variety of microorganisms including bacteria, fungi and protozoa. Gastrointestinal ecosystem, especially the rumen is emerging as an important source for enrichment and natural selection of microbes adapted to specific conditions. It represents a virtually untapped source of novel products (e.g. enzymes, antibiotics, bacteriocins, detoxificants and aromatic compounds) for industrial and therapeutic applications. Several gastrointestinal bacteria and fungi implicated in detoxification of anti-nutritional factors (ANFs) can be modified and manipulated into promising system for detoxifying feed stuffs and enhancing fibre fermentation both naturally by adaptation or through genetic engineering techniques. Intestinal lactobacilli, bifidobacteria and butyrivibrios are being thoroughly investigated and widely recommended as probiotics. Restriction endonucleases and native plasmids, as stable vectors and efficient DNA delivery systems of ruminal and intestinal bacteria, are increasingly recognised as promising tools for genetic manipulation and development of industrially useful recombinant microbes. Enzymes can improve the nutrient availability from feed stuffs, lower feed costs and reduce release of wastes into the environment. Characterization of genes encoding a variety of commercially important enzymes such as cellulases, xylanases, $\beta$-glucanases, pectinases, amylases and phytases will foster the development of more efficacious and viable enzyme supplements and enzyme expression systems for enhancing livestock production.

• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.755-768
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• 1998

Nitrogen and phosphorus are major nutrients in animal feeds which partially remain in the environment as pollution. In addition, nitrogen and phosphorus along with energy are the main nutrients which determine the feed cost. Any decreases in the levels of these three nutrients can contribute to reducing the pollution problem as well as the cost of feed. The nutrient requirements for chickens in the work here reported should allow for the addition of mixed enzymes (phytases, proteases, glucanases, xylanases and others). Such minimal levels of crude protein in the research results which are here reported are 16% for 0-6 weeks of age, 13.5% for 7-12 weeks of age, 11.5% for 13-18 weeks of age for layer type chicks, 13% for layer, 18% for 0-3 weeks of age broiler and 16.5% for 4-7 weeks of age broiler. These research projects have been done without adding enzyme supplements to their experimental diets. The minimal values of phosphorus, shown as available phosphorus, are 0.25% for pullets, 0.09% for layers and 0.25% for broilers with the addition of phytase. The minimum energy requirement (metabolizable energy) for reducing the feed cost could be summarized as 2,750 kcal per kg feed for pullets, 2,800 kcal for layers and 2,700 kcal for broilers.

• Mycobiology
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• 제33권4호
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• pp.223-229
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• 2005

A novel fungal strain Aspergillus sp. L117 that produced acid-stable and thermostable phytase was isolated on basis of the clearing zone on PSM plate and the ability of Na-phytate hydrolysis. The phytase of isolate showed a 3-fold higher activity than that of A. ficuun NRRL3135. The Aspergillus sp. L117 produced maximal level of phytase at initial pH of 5.0 and $30^{\circ}C$. The optimal pH and temperature for phytase activity were 5.5 and $50^{\circ}C$, respectively. The phytase showed totally stable activity after 20 min of exposure between 30 and $90^{\circ}C$, and even at $100^{\circ}C$. The highest level of residual phytase activity was obtained at pH 5.5, and still retained the stability at the broadest pH ranges (2.0 to 7.0) of all the aforementioned phytases. Storage stability of phytase was preserved over 96% of initial activities for 60 days at 4, -20, and $-70^{\circ}C$ and to retain even 70% of the initial activity at room temperature.

• 농업과학연구
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• 제49권3호
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• pp.463-481
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• 2022

Phosphorous (P) is considered to be one of the key essential elements demanded by crop plants. Approximately 70 - 90% of phosphatic fertilizers applied to crops are fixed in soil as Ca, Fe, and Al metal cations, which are insoluble and thus not readily available for plant uptake. Therefore, most soils are deficient in plant available P. This is usually rectified by applying phosphate fertilizers continuously, although this is not economically viable or environmentally acceptable. The present paper reviews the mechanisms involved with phosphate solubilization and mineralization by phosphate solubilizing microorganisms (PSMs) with the associated factors that determine the success. PSMs are effectively involved in mediating the bioavailability of soil P. Their contribution includes mineralization of organic P solubilization of inorganic P minerals, and storing sizable amounts of P in biomass through different mechanisms such as the production of organic and inorganic acids, H₂S, siderophores, exopolysaccharides, and production of enzymes such as phosphatases, phytase, and phosphonatases/C-P lyases, which are capable of chelating the metal ions, forming complexes, and making plant available P. PSMs manifest a wide range of metabolic functions in different environments, resulting in significantly higher plant growth, enhanced soil properties, and increased biological activities. Therefore, development of bio-inoculants with efficient novel PSM strains and further investigations on exploring such strains from diverse ecological niches with multifunctional plant-growth-promoting traits are needed.